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// Copyright (C) 2018 André Bargull. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-array.prototype.lastindexof
description: >
Calls [[HasProperty]] on the prototype to check for existing elements.
info: |
22.1.3.15 Array.prototype.lastIndexOf ( searchElement [ , fromIndex ] )
...
2. Let len be ? ToLength(? Get(O, "length")).
...
4. If fromIndex is present, let n be ? ToInteger(fromIndex); else let n be len-1.
...
7. Repeat, while k ≥ 0
a. Let kPresent be ? HasProperty(O, ! ToString(k)).
b. If kPresent is true, then
i. Let elementK be ? Get(O, ! ToString(k)).
...
includes: [proxyTrapsHelper.js]
features: [Proxy]
---*/
var array = [5, undefined, 7];
Object.setPrototypeOf(array, new Proxy(Array.prototype, allowProxyTraps({
has: function(t, pk) {
return pk in t;
}
})));
var fromIndex = {
valueOf: function() {
// Zero the array's length. The loop in step 8 iterates over the original
// length value of 100, but the only prototype MOP method which should be
// called is [[HasProperty]].
array.length = 0;
return 2;
}
};
Array.prototype.lastIndexOf.call(array, 100, fromIndex);
reportCompare(0, 0);
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